Re: "Hot standby"? - Mailing list pgsql-hackers

From Robert Haas
Subject Re: "Hot standby"?
Date
Msg-id 603c8f070908111200tbc89acmcf80875173b3a362@mail.gmail.com
Whole thread Raw
In response to Re: "Hot standby"?  (Ron Mayer <rm_pg@cheapcomplexdevices.com>)
List pgsql-hackers
On Tue, Aug 11, 2009 at 2:10 PM, Ron Mayer<rm_pg@cheapcomplexdevices.com> wrote:
> David Fetter wrote:
>> On Tue, Aug 11, 2009 at 08:56:38AM -0500, Kevin Grittner wrote:
>>> Bruce Momjian <bruce@momjian.us> wrote:
>>>
>>>> OK, so it is "warm slave".
>
> Why isn't it just a "read only slave".  Do some systems
> have read-only slave databases that can't serve as a warm
> standby system as well as this one could?

I think that's about right.  What we have now via pg_standby or
similar tools is a warm standby.  What this tool does is makes the
warm-standby also serve as a read-only slave.  It doesn't make
failover any simpler so it's not making the standby any hotter - it
instead makes the standby be able to do more useful work when no
failover has occurred.

The technical description for the commit message is probably something
like this:

"Allow read-only queries to be processed during archive recovery."

The P/R version is probably something like this:

"Warm standby servers now function as read-only slaves."

...Robert


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